Got Pollution? Get Rust

Wei-Xian Zhang, an environmental engineer at Lehigh University in Pennsylvania, has decontaminated a 1,000-square-foot plot at a pharmaceutical plant in North Carolina using just $1,000 in raw materials. His secret: 20 pounds of iron nanoparticles—superfine iron dust.

As iron rusts, it unleashes electrons that can break down organic pollutants such as dioxins, PCBs, and many pesticides. By growing iron atoms into incredibly small particles, Zhang increases the number of electrons they release as much as 1,000-fold. He then mixes the ultrafine powder with water so it can be pumped into the ground. A few days after injecting the iron powder into contaminated land, all that is left behind are simple, nontoxic hydrocarbons. The iron dust eventually dissolves harmlessly into the groundwater. Early next year, Zhang plans a larger test, treating a 100-acre site in North Carolina. He is also developing a commercial version of the process.